Greywater recycling

What is greywater recycling?

'Greywater' refers to all wastewater generated in buildings from streams without fecal contamination – i.e. all streams except for the wastewater from toilets. Greywater recycling, then, refers to the treatment of wastewater from appliances such as showers, baths and sinks, to be re-used and fed back into a property for non-potable purposes such as flushing toilets.

How does a greywater recycling system work?

First, wastewater is collected from appliances and fed into a collection unit (via pumps or gravity). The collection unit removes contaminants using biological, chemical and physical actions.

From here, the wastewater is pumped into a treatment system for 'ultrafiltration' which prevents particles, bacteria and viruses from passing through to the next stage of the system.

The treated water is stored in a tank before being pumped out for re-use in toilet flushing or irrigation on-demand (the greywater cannot sit for extended time periods in the tank otherwise it is at risk of becoming contaminated).

What are the business benefits of greywater recycling?

Greywater recycling is most suited to businesses that need a constant supply of water for use in baths, basins and toilets. In this regard, hotels, large offices, residential blocks and leisure centres will find the system particularly attractive.

Greywater can account for 30-50% of the wastewater that is discharged into sewers. While it is likely that treated greywater will not be safe to drink, recycling it can significantly reduce water bills for businesses.

Greywater recycling has been shown to reduce water consumption by up to 40%. According to Thames Water, London is set to suffer from a shortfall of water of 414 million litres a day by 2040, meaning that the cost of water will rise with demand.

Some greywater recycling systems allow businesses to save on water costs without any changes to staff behavior and actions. For instance, the systems can be fitted with built-in telemetry to transmit system data and live diagnostics, giving businesses greater maintenance over their water systems.

Alongside reductions to water footprints, greywater recycling can reduce carbon emissions and energy use – some low-energy systems are capable of produce a cubic metre of of water using just 1.5kw/h energy.

It should also be noted that greywater recycling systems will compliment other on-site sustainability solutions and can increase credits for companies attempting to secure BREEAM or LEED building standards.

How much does a greywater recycling system cost?

There is no single figure for the installation costs of a rainwater harvesting system – it will fluctuate based on the size of the system and whether it is being retrofitted into existing infrastructure.

Payback on a greywater recycling system generally ranges from 2.5 to five years, based on whether the system is 'on-demand' or 'batch'. A batch system uses a low-pressure filtration method which has lower energy consumption, but more space is required for the tanks. An on-demand system is smaller and takes a high-pressure approach to deliver rapid ultrafiltration. Installation costs are lower, giving a faster return on investment. 

It should also be noted that businesses that install greywater recycling systems are also eligible for the Enhanced Capital Allowance (ECA) initiative to reduce upfront expenditure. ECA allows business to claim a tax relief for the first year of investment. For water recycling projects, ECA covers 100% of the first-year allowance of investments, writing the project off against taxable profits.

What are the key business requirements when intalling a greywater recycling system?

Ideally, greywater recycling systems should be designed as a building specification prior to the construction of the building. Specific pipework and the need for space for the filtration and storage tanks makes retrofitting a costly undertaking.

Installations are usually managed by a dedicated technical account manager from an installer, who will provide site-specific advice to the business once completed. Once in place, greywater recycling systems will require annual inspections and are low-maintenance.

A system with built-in telemetry will gather real-time data for the system, so businesses can be preventive to any issues and manage the system more thoroughly. Some online platforms – such as Waterline – will run reports on the performance of the system. Businesses can used these platforms to verify water savings.

How does greywater recycling differ from other water re-use systems?

Greywater recycling systems utilise the wastewater from internal appliances in a building. This excludes wastewater contaminated through toilet discharges, which can be treated through blackwater systems. Greywater is easier to treat compared to blackwater because no faecal matter can leak harmful pathogens into the water.

Greywater recycling is different to rainwater harvesting, which collects rainwater as an alternative source of water. Greywater recycling systems usually have a quicker return on investment than rainwater recycling systems, and benefit from not depending on weather circumstances. While rainwater harvesting can reduce water consumption by around 30%, it is estimated that greywater recycling systems can deliver up to 40% in water savings. 

Related items

Mission Possible: The 2019 report

This exclusive edie report showcases world-leading and potentially game-changing examples of sustainability in action across the Mission Possible campaign's five pillars: Energy, Resources, Mobility, The Built Environment and Business Leadership.

45-minute masterclass: Streamlined Energy & Carbon Reporting (SECR) for business

This live, online masterclass helps sustainability and energy professionals get to grips with Streamlined Energy and Carbon Reporting (SECR), which came into force in April 2019 and affects almost 12,000 businesses across the country.

In-house download. UK Resources & Waste Strategy: A blueprint for business leadership

This edie insight guide provides sustainability and environmental professionals with a detailed breakdown of all of the key elements of the UK Government's Resources and Waste Strategy, and what they mean for business.

Business Energy Barometer: April-May 2019

edie's brand-new Business Energy Barometer report maps out the key energy drivers, challenges and opportunities facing UK businesses, based on an in-depth survey of energy managers across the country.

In action: edie publisher's AI-assisted IT software to reduce energy

In an effort to 'walk the walk' with sustainability' and reduce carbon emissions, edie's parent company Faversham House has trialled innovative computer software to measure, manage and ultimately reduce associated energy.

£200,000 of the fine will be donated to environmental charities across Oxfordshire

Thames Water hit with £2m fine for 'avoidable' sewage leak

Utility firm Thames Water has been ordered to pay a £2m fine by the Environment Agency (EA), after raw sewage from one of its pumping stations was found to have leaked into Oxfordshire's waterways.

Webinar: Ambition into action: Scaling-up your energy and resources strategy

This one-hour webinar will hear from the leading businesses and experts that are reaching the ‘climate turning point' by scaling-up efforts to drastically reduce energy and resource use through net-zero targets and strategies.

Accelerating the rEVolution: 7 business innovations in e-mobility

This insight report, produced in partnership with UK Power Networks Services, investigates some of the game-changing developments which are driving e- mobility and accelerating the sector forward into the next decade.

The sustainability communications handbook: Engaging with different audiences

Communication is a vital component of any organisation's strategy - and an aspect which businesses of all sizes and sectors will have to continually fine-tune as digitisation progresses. Similarly, sustainability is now widely considered to be a business-critical consideration and a must-have for staff, consumers and investors alike.

edie Explains: Streamlined Energy and Carbon Reporting (SECR)

What is the Streamlined Energy and Carbon Reporting (SECR) framework? What do businesses need to know about this new piece of legislation? And what compliance issues will arise from the new framework? This free edie Explains guide gives you everything you need to know.

The Every Drop ambition for 2030 commits Heineken to maximise water circularity in water-stressed areas to treat 100% of its wastewater worldwide

Why Heineken is championing water circularity as its contribution to the SDGs

EXCLUSIVE: Brewer Heineken has called for more collaborative and circular approaches to water use, after launching a new 2030 strategy aligned with the UN Sustainable Development Goal 6 - Clean Water and Sanitation.

The climate turning point: 8 sustainable business gamechangers for 2020

With the UK having just declared a climate emergency and Government advisers calling on policymakers to set a net- zero carbon target by 2050, edie's latest report explores eight potentially game-changing innovations that will help businesses lead the charge towards the so-called 'climate turning point'.

Sustainable Business Leadership Survey 2019 - The results...

This brand new annual survey reveals exactly what ‘business leadership' now looks like from the perspective of sustainability, CSR and energy professionals across the UK.

Five ideas to achieve your flexible energy future

This report showcases the output of edie's SPARK! event, where roundtable participants explored what lies ahead for electricity systems flexibility, and discussed the practical steps that can be taken to achieve flexible energy, today.

edie Explains: Energy-from-Waste

Is Energy-from-Waste (EfW) right for your business? What are the different EfW technology options, and how do you choose the right one? This edie explains business guide, produced in association with phs Group, has the answers.

Heineken notably operates breweries, cider plants and offices in six UK cities

Heineken granted water self-supply licence for UK operations

Brewer Heineken has been granted a self-supply licence to deliver its own water and wastewater services for all of its UK operations, in a move it claims will bolster its water stewardship efforts.

10 ideas to make energy innovation work for your business

This report showcases the output of edie's SPARK! event, where roundtable participants discussed the role of innovation in achieving a sustainable future for business energy and debated which new technologies could hold the key to clean growth.

edie Explains: The circular economy

This new and updated edie Explains guide breaks down everything there is to know about achieving a circular economy for your business.